Go to www.smspeople.net, upload your list of phone numbers. You'll receive a code that you can use to download the list into your phone. Create a group, go to settings and download the phone numbers. Don't worry, the phone numbers on the list won't mix with your contacts.
Well that's it! You select a group, type a message, then send. SMS People will diligently send the texts one after another, whether you or sleep or awake. It can send hundreds.... Just remember to buy SMS bundles before you send, right?